Does weight training give women big muscles? Will eating a main meal after 6pm be disastrous for your waistline? Do sit-ups help to zap a spare tyre?
Almost every day we hear another piece of conflicting health advice, whether from scientists, the fitness industry or friends. But if you want to get fit and stay in shape how can you find out what information is true and what is false?
Here we explode eight health and fitness myths.
Do you burn as many calories walking a mile and running a mile?
The argument: Those who walk say it's better for your joints and burns as many calories as running. Those who run laugh at this idea and claim that they must surely use more energy over a mile, regardless that it takes half the time, because they are working harder.
The facts: Top exercise physiologists found that a 70kg man will burn 5 calories a minute walking at 3.5mph and 18.2 calories a minute running at 10mph. To save your maths, per mile this equates to 85 calories expended during a one-mile walk and 109 calories in a one-mile run. But this difference amounts to only 24 cals.
Where the real difference occurs is post-exercise. The energy demands of leg muscles after running are much greater than after walking, and can be as great as twice the amount as after walking.
Added to this is the fact that most runners will tend to run for two or three times as long as walkers, covering a much further distance.
Will doing 200 sit-ups a day help me to burn off my spare tyre?
The argument:Many people believe that sit-ups or crunches are the only way to achieve a flatter stomach.
The facts: While sit-ups will help to strengthen and firm up the rectus abdominus muscles (the abs) they will nothing to reduce the amount of fat you have on your tummy.
The only way to shift abdominal fat is to work if off by reducing calories eaten and performing high-intensity cardiovascular exercise, such as running or cycling.
Is olive oil good for you if you're on a diet?
The argument: Olive oil is a monounsaturated fat, which is scientifically proven to offer protection from heart disease and some cancers.
The facts: What most people forget is that olive oil is still a fat. Whether you eat lard, butter or olive oil it still contains 9kcal per gram. Although unsaturated fats are far healthier than saturated fats they will still lead to weight gain if you consume too much. So keep olive oil to a minimum.
A hot bath is the perfect remedy for a pulled muscle.
The argument: Many people jump into a hot bath following a hard exercise session or as a way to relieve the pain of a strained muscle.
The facts: When you strain a muscle bruising breaks out as a result of broken blood vessels. Research shows that the worse thing you can do when these vessels are still bleeding is to apply anything hot, because this only encourages the vessels to dilate and bleed some more.
The correct procedure is to reduce the flow of the blood by applying ice. The best remedy is to jump in an ice-cold bath, not a hot one.
Weight training gives women big muscles.
The argument: Many women avoid weight training because they believe that it will lead to bulky, unattractive muscles.
The facts: First, muscle is very hard to build and especially so for most women who have a distinct lack of the muscle-building hormone testosterone.
Actually what happens is that when women lift weights it gives the appearance of smaller muscles.
This is because women's muscles contain a higher level of fat than a man's. And when you perform high-intensity exercise, such as weight training, the metabolism is increased and the fat is freed from the muscles to fuel the energy demands of exercise.
As a result the female body will end up looking leaner and more toned, rather than like a Russian shot-putter.
You shouldn't eat carbohydrates after 6pm is you want to lose weight.
The argument: Many dieters believe that eating a main meal of carbs, such as pasta or potatoes, later in the day will lead to bigger weight gains.
The facts: There is no evidence to prove that eating carbs after 6pm will cause a greater fat store than at any other time of the day. The rate of digestion in your intestines is just the same at night as it is in the early hours of the day.
What does make the difference is an over-consumption of food late in the day, not the type of food you eat. And because carbs can often be high in calories then it is easy to over-eat during a late evening meal.
So to lose weight or stay in shape keep the overall balance of carbs and calories in check throughout the day.
Exercise is not necessary for losing weight because all I have to do is diet.
The argument: There are numerous weight loss pans that simply restrict the calories you eat. Many claim that this is enough to shed the pounds, and that exercise is not required.
The facts: In a study of two groups of men with mild obesity both followed the same diet plan, and only one followed an exercise programme.
While both groups lost a similar amount of weight, the exercise-plus-diet group lost a great deal more fat and no fat-free mass, such as muscle.
What is significant is that muscle is an active metabolic tissue that needs energy to exist. If you lose muscle your metabolic rate drops and you use up less energy calories while at rest.
So the best way to lose weight and stay slim is to burn off fat not muscle and the best way to do this is with exercise.
Muscle turns to fat when you stop exercising.
The argument: This is one of the most common reasons that people give for not weight training.
The facts: Muscle is made up of a totally different molecular structure to fat, making it biologically impossible for it to turn to fat. The myth exists because many muscular athletes find it hard to change their eating and lifestyle habits after years of intense exercise and all too often put on gain weight as fat.
